NAIROBI, Kenya  More than 70 percent of Africans depend on the continent's natural resources for their livelihoods, but the toll taken on land and water could cause economic havoc if environmental protection is not given a high priority, a U.N. report said.

The program's executive director, Achim Steiner, said Tuesday that the report also found that if managed properly, Africa's natural resources could offer a way out of poverty.

"Africa is often associated as being a dry continent," Steiner said. But "there are vast water resources on this continent, the question is one of management, distribution and equitable access."

While the 542-page report only offered anecdotal economic data, Steiner insisted that the key to Africa's development was the proper conservation and exploitation of the continent's natural resources.

The report found that only about five percent of Africa's development potential from freshwater resources is being used for "industry, tourism and hydropower."

"The very reason poverty is not more extreme in Africa today is because of how people have managed to utilize the natural resource base to survive in anticipation of the great promise of economic development," he said.

He added that very few economists have bothered to try to understand the benefits, both social and environmental, that Africa's natural resources have to offer.

"As Africa develops its economies, it is in the natural resource base that its greatest potential lies," Steiner added.

But the report also warned of disaster, both environmental and economic, if steps are not taken to protect Africa's natural resources.

"If policies remain unchanged, political will found wanting and sufficient funding proves to be elusive, Africa may take a far more unsustainable track that will see an erosion of its nature-based wealth and a slide into ever deeper poverty," Steiner said.

Africa is home to more than 800 million people, about 13 percent of the world's population, and is the poorest continent in the world, with most people surviving on less than US$1 a day. The report found that most African's rely on some form of agriculture for survival, making them vulnerable to environmental changes.

Under a worse case scenario, the report found that between 25,000 hectares (61,775 acres) and 35,000 hectares (86,500 acres) of farming land a year could be lost as a result of degradation by 2025.

Species foreign to Africa, from toads to trees, will also continue to damage Africa's environmental and economic well-being, the report said. They cause millions of dollars (euros) in damage annually and undermine economic progress, it said.

The report also found that multinational companies have increased the production of dangerous chemicals in Africa by 2.5 percent a year since 1976 and that abandoned chemical stockpiles have become a threat.

"More than 50,000 tonnes (56,000 U.S. tons) of obsolete pesticides have been accumulated in Africa, contaminating tons of soil," the report said. "The management of obsolete chemicals, stockpiles and waste management presents a serious threat to human well-being and the environment."

Genetically modified crops have been the subject of intense debate in Africa, with advocates arguing that they are needed to increase food production, but critics insisting they are dangerous, the report said.

Many African countries do not have the scientific, legal, risk assessment and administrative structures in place to deal with the potential problems cause by genetically modified crops, the report said.